src/app/CommandHandlerInterfaceRegistry.cpp

/**
 *    Copyright (c) 2024 Project CHIP Authors
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
#include <app/CommandHandlerInterfaceRegistry.h>

using namespace chip::app;

namespace chip {
namespace app {

CommandHandlerInterfaceRegistry & CommandHandlerInterfaceRegistry::Instance()
{
    static CommandHandlerInterfaceRegistry registry;
    return registry;
}

void CommandHandlerInterfaceRegistry::UnregisterAllHandlers()
{

    CommandHandlerInterface * handlerIter = mCommandHandlerList;

    //
    // Walk our list of command handlers and de-register them, before finally
    // nulling out the list entirely.
    //
    while (handlerIter)
    {
        CommandHandlerInterface * nextHandler = handlerIter->GetNext();
        handlerIter->SetNext(nullptr);
        handlerIter = nextHandler;
    }

    mCommandHandlerList = nullptr;
}

CHIP_ERROR CommandHandlerInterfaceRegistry::RegisterCommandHandler(CommandHandlerInterface * handler)
{
    VerifyOrReturnError(handler != nullptr, CHIP_ERROR_INVALID_ARGUMENT);

    for (auto * cur = mCommandHandlerList; cur; cur = cur->GetNext())
    {
        if (cur->Matches(*handler))
        {
            ChipLogError(InteractionModel, "Duplicate command handler registration failed");
            return CHIP_ERROR_INCORRECT_STATE;
        }
    }

    handler->SetNext(mCommandHandlerList);
    mCommandHandlerList = handler;

    return CHIP_NO_ERROR;
}

void CommandHandlerInterfaceRegistry::UnregisterAllCommandHandlersForEndpoint(EndpointId endpointId)
{
    CommandHandlerInterface * prev = nullptr;

    for (auto * cur = mCommandHandlerList; cur;)
    {
        // Fetch next node in the list before we remove this one.
        auto * next = cur->GetNext();

        if (cur->MatchesEndpoint(endpointId))
        {
            if (prev == nullptr)
            {
                mCommandHandlerList = cur->GetNext();
            }
            else
            {
                prev->SetNext(cur->GetNext());
            }

            cur->SetNext(nullptr);
        }
        else
        {
            prev = cur;
        }

        cur = next;
    }
}

CHIP_ERROR CommandHandlerInterfaceRegistry::UnregisterCommandHandler(CommandHandlerInterface * handler)
{
    VerifyOrReturnError(handler != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
    CommandHandlerInterface * prev = nullptr;

    for (auto * cur = mCommandHandlerList; cur; cur = cur->GetNext())
    {
        if (cur->Matches(*handler))
        {
            if (prev == nullptr)
            {
                mCommandHandlerList = cur->GetNext();
            }
            else
            {
                prev->SetNext(cur->GetNext());
            }

            cur->SetNext(nullptr);

            return CHIP_NO_ERROR;
        }

        prev = cur;
    }

    return CHIP_ERROR_KEY_NOT_FOUND;
}

CommandHandlerInterface * CommandHandlerInterfaceRegistry::GetCommandHandler(EndpointId endpointId, ClusterId clusterId)
{
    for (auto * cur = mCommandHandlerList; cur; cur = cur->GetNext())
    {
        if (cur->Matches(endpointId, clusterId))
        {
            return cur;
        }
    }

    return nullptr;
}

} // namespace app
} // namespace chip